1. Technical Field
A surgical cutting instrument which employs a fluid jet to cut tissue is provided, where the fluid jet exits the instrument as a high pressure fluid pulse generated from a low pressure fluid input.
2. Background of the Related Art
There has recently been increased interest in the medical community in developing cutting instruments which are highly accurate and which reduce trauma to surrounding tissue to significantly reduce recovery time for the patient. Many new technologies have been utilized in the development of these cutting tools, and as a result there has been increased use of laser tools, electrocautery type tools, ultrasonic emulsification tools, and fluid jets which are very accurate and which allow the surgeon to perform the procedure only on the tissue which is the intended target. However, tools which utilize laser, electrocautery and ultrasonic energy techniques by design generate heat which may in turn cause some damage to surrounding tissue.
On the other hand, fluid jet cutting instruments minimize the potential for damage to surrounding tissue since there is no generation of heat, and the controlled fluid streams may be very localized to permit the surgical procedure to be performed in very close locations. The fluid jet cutters typically are utilized to remove soft tissue, since the fluid jet tends to emulsify soft tissue which is easily removed by aspiration from the surgical site. In particular, fluid jet cutters are utilized in such surgeries as ocular surgery, brain surgery, and other soft tissue surgical procedures. The fluid jet may be controlled by forming discrete pulses, which increases its cutting ability, minimizes the amount of excess fluid present at the surgical site and diminishes the possibility of inadvertent or unintended surgical trauma. As the emulsification of the soft tissue is occurring, it is common to provide an aspiration device which simultaneously removes the excess fluid and emulsified tissue from the surgical site.
However, many of the prior fluid jet cutting devices suffer disadvantages which makes their use a concern to surgeons. In particular, the prior devices generally require external pressurizing sources which provide the instrument with the high pressure fluid jet, so that the curing device is always operating at a high pressure. In addition, many of these devices further require an external or remote pulsing device to provide the fluid pulses at the surgical site. This affords less control to the surgeon, and may also cause an excessive amount of fluid to remain present at the surgical site. Furthermore, unless the pressure is carefully regulated, a steady stream of pulses or a continuous stream of fluid may quickly penetrate into the soft tissue and Cause catastrophic damage. Accordingly, highly skilled personnel must be present during the surgical procedure to perform the cutting procedure with the fluid jet. These prior fluid cutting devices do not inherently prevent high pressure streams or continuous pulses, and must be carefully controlled by the external device and the personnel to avoid serious accidents.
While it is known in some prior devices to provide a pressure generating mechanism in the handle of the instrument itself, these devices generally require a high pressure gas source and a high pressure fluid input which must be carefully regulated by valves and/or pressure relief devices in the instrument itself. Furthermore, these instruments require a large amount of mechanical components, such as springs and check valves to regulate the pressure and provide pulses of fluid at the surgical site.
Therefore, a need exists for a surgical cutting instrument using a fluid jet pulse in which the high pressure fluid pulse is generated in the body of the instrument itself from a low pressure fluid input Furthermore, a need exists for a fluid jet cutting instrument which minimizes the number of mechanical parts to significantly reduce the possibility of mechanical fatigue and failure of the parts. A further need exists for a surgical fluid jet cutting instrument, which utilizes a low pressure gas source to create a high pressure fluid output pulse from a low pressure fluid input.